Optical discs are available as information recording media having sector structures. In recent years, an AV data in audio and video are digitalized and higher-density and larger-capacity optical discs have been developed. The optical discs can be broadly classified into three types, depending on the characteristics thereof. First one is a reproduction-only disc in which data is recorded using bumps and pits of the disc and a user cannot record a new data. Second one is an additionally recordable disc that has a recording film of organic dye or the like to allow recording only once. Third one is a rewritable disc that has a recording film of a phase change material or the like to allow recording multiple times (i.e., rewriting).
In general, the additionally recordable discs are highly compatible with reproduction-only discs and can be manufactured at relatively low cost for the reason of manufacturing facilities, and thus have become increasingly widespread in recent years. As typical additionally recordable discs, DVD-R (Digital Versatile Disc Recordable) and CD-R (Compact Disc Recordable) are widely used.
However, an additionally recordable disc requires control specific to the additionally recordable disk since a recorded data and a management information thereof can not be written. Hereafter, an additionally recordable disk is described with reference to an example of a DVD-R disc.
FIGS. 1A to 1C are illustrations explaining a case in which data is recorded on a DVD-R disc multiple times.
FIG. 1A shows a data structure of a DVD-R disc 100 in which a user data area 102 for recording data specified by a user is in an unrecorded state. An RMA (Recording Management Area) located at an inner circumference portion is an area for managing the recording state of the user data area 102. In the DVD-R, additionally recordable areas are managed in areas called RZones (Reserved Zones). In FIG. 1A, an RZone #1 exists as only one additionally recordable area.
FIG. 1B shows a state in which three additionally recordable areas RZone #1, RZone #2, and RZone #3 are allotted. Portions indicated by hatching represent already-recorded areas. In this manner, when a recording operation in which unrecorded area is sandwiched is performed, a reserving operation for RZone is required in order to manage an additionally recordable location on the DVD-R disc. A start address for each RZone and an LRA (Last Recorded Address) indicating the last recorded location in each RZone are managed in an RMA 101. A border closing process is required in order that a disk shown in FIG. 1B is reproduced by a reproduction-only apparatus, such as DVD-ROM (Digital Versatile Disc Read Only Memory) drive. The border closing process is performed in order to avoid the restriction that the reproduction-only apparatus cannot access an unrecorded area on the disc.
FIG. 1C shows a data structure after the border closing process is performed. Data is recorded so that no unrecorded area exists in the RZones and a border-out (Bout) area 110 is recorded in an end of the border area. The border-out area 110 prevents the reproduction-only apparatus from improperly accessing an unrecorded area. An RZone #4 which is available for the next recording is generated subsequent to a border area #1 recorded as described above.
FIG. 2 shows a data structure for the RMA 101.
The RMA 101 is an area for storing RMDs (Recording Management Descriptors) for managing information on the RZones. The RMDs are updated when a new RZone is reserved or when the disc is ejected from the recording apparatus. Since a new RMD is updated in a subsequent area, a latest RMD 120 is recorded at the end of a recorded area (i.e., immediately prior to an unrecorded area).
The latest RMD 120 includes a disc identification information 121 for identifying a type of disc, an OPC (Optimum Power Calibration) information 122 for storing an adjustment result of recording power or the like, a border management information 123 for storing management information regarding a border and an RZone management information 124 for storing management information regarding an RZone.
The RZone management Information 124 stores information regarding each RZone. Hereafter, the case shown in FIG. 1B is used for describing the RZone management information 124. Since a last RZone number 125 stores the last RZone number allotted on the disc, “3” indicating a reserved RZone #3 is stored as an RZone number. “1” indicating a reserved RZone #1 and “2” indicating a reserved RZone #2 are respectively stored in a reserved RZone #1 number 126 and a reserved RZone #2 number 127. In a case of DVD-R, the number of reserved RZones that are not closed is limited to a maximum of 2. An address indicating the start location of the RZone #1 area is stored in an RZone #1 start address 128. An address indicating the last location of a recorded area in the RZone #1 is stored in an RZone #1 LRA 129. However, since the RZone #1 LRA 129 is not updated every time, there are some cases in which the RZone #1 LRA 129 does not match a last recorded location, e.g., a case in which power supplied to the recording apparatus is interrupted at unexpected timing. In such cases, based on the information in the RZone #1 LRA 129, the recording apparatus searches to determine whether or not a subsequent area is unrecorded to detect a true last recorded location. The start address and the last recorded address of the RZone #2 area are respectively stored in an RZone #2 start address 130 and an RZone #2 LRA 131.
FIG. 3 is a flowchart showing a process when a DVD-R disk, which is a conventional additionally recordable information recording medium, is loaded in a recording apparatus. Hereafter, details of the process are described with reference to the flow.
Upon determining that the loaded information storage medium is a DVD-R disc, the recording apparatus searches for the end of a recorded-area in the RMA area in order to obtain the latest RMD. Based on a reproduction signal or the like from the disc, the recording apparatus sequentially determines whether an area is a recorded area or an unrecorded area to search for a border between the recorded area and the unrecorded area (step S301).
Upon detecting the border between the recorded area and the unrecorded area, the recording apparatus determines that the last area of the recorded area is the latest RMD, and then executes a reading process (step S302).
Based on the content of the latest RMD area read from the disc, the recording apparatus determines whether or not the content of the latest RMD has an additionally recordable reserved RZone. When an additionally recordable reserved RZone is detected, the process proceeds to step S304, and when an additionally recordable reserved RZone is not detected, the process proceeds to step S305 (step S303).
When an additionally recordable reserved RZone is detected in step S303, the recording apparatus searches for a subsequent area from the LRA of the reserved RZone. This is intended to obtain a true last recorded location by searching for the subsequent area since an LRA may not correspond to a true last recorded location as described above. The recording apparatus internally stores, as a true LRA, an address of an area immediately prior to the border between the recorded area and the unrecorded area, the border being initially detected in the area subsequent to the LRA. Thereafter, the process proceeds to step S303 in order to determine whether or not another additionally recordable reserved RZone exists (step S304).
The recording apparatus which has completed the LRA searching in all reserved Rzones performs as last step an LRA searching in the last RZone. In an area subsequent to the LRA stored in the latest RMD, the recording apparatus searches for the border between the recorded area and the unrecorded area, as in the same way as the process in step S304, and detects a true LRA and internally store the true LRA (step S305).
Due to the process flow described above, the recording apparatus obtains all recordable addresses on the disc and internally stores the addresses.
FIG. 4 is a flowchart showing a process for newly reserving an RZone for managing a recorded location. Hereafter, details of the process will be described with reference to the flow. In the following description, the recording apparatus receives an RZone reserving instruction from a high-order controlling means such as a personal computer and an area length of an RZone to be reserved.
The recording apparatus which has received a new RZone reserving instruction determines whether or not the number of new RZone reserving instructions does not exceed a predetermined number of reservable RZones (up to two in case of a DVD-R disc). When it is determined that reserving a new RZone causes the number of reservable RZones to be exceeded, the process completes as error. When it is determined that reserving a new RZone does not cause the number of reservable RZones to be exceeded, the process proceeds to step S402 and the RZone reservation process continues (step S401).
The recording apparatus secures an RZone area length specified by the high-order controlling means at a first portion in the last RZone. The starting location of the last RZone is also updated so as to be subsequent to the area reserved as a newly reserved RZone. The recording apparatus performs reading from the disc, stores the start address of the newly reserved RZone and the LRA in the internally stored RMD information and updates the start address of the last RZone (step S402).
The recording apparatus records the RMD which is updated in step S402 at the start area of an unrecorded area in the RMA, i.e., an area immediately subsequent to the latest RMA (step S403).
As described above, the recording apparatus updates the content of the RMD upon receiving a new RZone reserving instruction.
FIG. 5 is a flowchart showing a recording procedure for recording a user data to a user data area 102 of the DVD-R disc illustrated in FIGS. 1A to 1C and 2. Hereafter, details of the process will be described below with reference to the flow. In the following description, the recording apparatus receives a recording start address, at which the user data is recorded, and a recording length, which indicates the data length of data to be recorded, as a control information from the high-order controlling means such as a personal computer. The recording apparatus refers to an internally held RMD information to determine whether or not the recording start address instructed by the high-order controlling means matches the recordable address of either an additionally recordable reserved RZone or the last RZone. Herein, the recordable address refers to an address of an area immediately subsequent to the last recorded address. When the recording start address instructed by the high-order controlling means does not match the recordable address of any of the additionally recordable RZones, the process completes as error. On the other hand, when the recording start address matches the recordable address of any of the additionally recordable RZones, the process proceeds to step S502 (step S501).
The recording apparatus refers to the Internally held RMD information to determine whether or not an additionally recordable area corresponding to the specified recording length remains in the additionally recordable RZone requested for recording. When an additionally recordable area corresponding to the specified recording length or more exists, the process proceeds to stop 6503, and when an additionally recordable area corresponding to the specified recording length or more does not exist, the process completes as error (step S502).
The recording apparatus receives the user data to be recorded from the high-order controlling means and records the transferred a user data to an area subsequent to the specified recording start address (steps S503 and S504).
When an unrecoverable error occurs In the recording process in step S504, the process completes as error. On the other hand, when no error occurs and all the specified user data is recorded, the process proceeds to step S506 (step S505).
When all user data transferred from all the high-order controlling means are properly recorded in step S505, the recording apparatus updates the RMD information stored in the memory of the apparatus. The last recorded address (LRA) of the RZone to which the user data was recorded is updated here (step S506).
As described above, the recording apparatus performs recording to an area subsequent to the additionally recordable location and updates the last recorded address of a recorded RZone. In step S506, the updated RMD information may be recorded on the disc. In general, however, due to the reasons of performance involving time required for recording and of a reduction in RMA area consumption, the RMD Information stored in the apparatus is recorded on the disc at timing such as during discharge of the disc.
FIG. 6 is a flowchart showing a process procedure for closing an RZone of the DVD-R disc illustrated in FIGS. 1A to 1C and 2. Hereafter, details of the process will be described with reference to the flow. In the following description, a closing instruction command and an RZone number to be closed as a control information are transferred from a high-order controlling means such as a personal computer.
Upon receiving the RZone closing instruction from the high-order controlling means, the recording apparatus determines whether or not the specified RZone is in an additionally recordable state. When it is determined that the specified RZone is in an additionally recordable state, the process proceeds to step S602 and the closing process continues. When it is determined that the specified RZone is not in an additionally recordable state, the closing process completes as error (step S601).
The recording apparatus refers to the RMD information stored in the apparatus to determine whether the RZone number for which the closing instruction was issued from the high-order controlling means corresponds to the last RZone or a reserved RZone. When it is determined that the closing instruction is for a reserved RZone, the process proceeds to step 6603, and when it is determined the closing instruction is for the last RZone, the process proceeds to step S605 (step S602).
The recording apparatus determines whether or not an unrecorded area exists in the RZone for which the closing instruction was issued. When an unrecorded area exists, the process proceeds to step S604, and when an unrecorded area does not exist, the process proceeds to step S605 (step S603).
In steps S602 and S603, when it is determined that the RZone for which the closing instruction was issued from the high-order controlling means is a reserved RZone and an unrecorded area exists in the reserved RZone, the recording apparatus records a NULL data (data for setting all user data to “0”) to all unrecorded areas in the reserved RZone for which the closing instruction was issued (step S604).
The RZone to be closed is deleted from the management of RZones in the RMD stored in the recording apparatus. Herein, the RZone deletion means, when a closed RZone is a reserved RZone, setting “0” in a reserved RZone number area in the RZone management information. When a closed RZone is the last RZone, the RZone deletion means setting the last RZone number area to a value increased by “1”. For example, in FIG. 2, when a reserved RZone #1 is closed, the reserved RZone #1 number 126 is set to “0”. As another example, in a case in which “3” is stored in the last RZone number 125, when an RZone number 3 to closed, the last RZone number 125 is set to “4”. Through the process as in the above-described examples, the information of the closed RZone is deleted from the RMD (step S605).
The recording apparatus records the RMD updated in step S605 in an unrecorded-area start area in the RMA i.e., an area immediately subsequent to the latest RMD, on the disc (step S606).
As described above, the recording apparatus performs the RZone closing process so that that any unrecorded area does not remain in the RZone.
Next, how a recorded user data is managed at the file system level in a conventional recording method will be described with reference to FIGS. 7A, 7B and 8.
FIGS. 7A and 7B show examples of files and directories to be recorded on the disc.
FIG. 7A shows an example in which a DIR-1 directory exists in a root directory and two files, namely, a FILE_A and a FILE_B further exist in the DIR_1 directory. FIG. 7B shows a structure in which a new DIR_2 directory is created in the root directory and two files, namely, a FILE_C and a FILE_D are added to the DIR_2 directory.
FIG. 8 is a layout view for illustrating a data structure of a file/directory management information for managing the file and directory structures shown in FIGS. 7A and 7B. A volume space structure is recorded in a volume structure 801. A file group descriptor 802 and a file entry 803 for the root directory (ROOT_DIR) are recorded in a file structure/file area 829. A VAT (Virtual Allocation Table) 804, which describes the allocation of a virtual logic address and a VAT ICB 805 which indicates a VAT recording location are recorded in a VAT structure 830. A VAT structure 832 and a VAT structure 834 are recorded in order to update the file management information when a directory and a file are additionally recorded.
When directories and files as shown In FIG. 7A are recorded, data for the volume structure 801 in the volume structure, the file structure/file area 829, the VAT structure 830, the file structure/file area 831, and the VAT structure 832 shown in FIG. 8 are recorded, and a file structure/file area 833 and the VAT structure 834 are unrecorded areas. The file structure/file area 831 contains a FILE_A 806 which is the file data of the file “FILE_A”, a FILE_A file entry 807 which stores the recording location and file attribute of the file data of the “FILE_A”, a FILE_B 808 which is the file data of the file “FILE_B”, a FILE_B file entry 809 which stores the recording location and file attribute of the file data of the “FILE_B”, a “DIR_1” file entry 810 which stores information regarding the directory “DIR_1” and a “ROOT_DIR” file entry 811 which stores information regarding the root directory “ROOT_DIR”. Virtual addresses for the file entries stored in the file structure/file area 831 are stored in the VAT structure 832, which will be described later.
Next, when a directory “DIR_2”, a file “FILE_C”, and a “FILE_D” as shown in FIG. 7B are additionally recorded, the file structure/file area 833 and the VAT structure 834 are additionally recorded to the disc. The file structure/file area 833 contains a FILE_C 814 which is the file data of the file “FILE_C”, a FILE_C file entry 815 which stores the recording location and file attribute of the file data of the “FILE_C”, a FILE_D 816 which is the file data of the file “FILE_D”, a FILE_D file entry 817 which stores the recording location and file attribute of the file data of the “FILE_D”, a “DIR_2” file entry 818 which stores information regarding the directory “DIR_2” and a “ROOT_DIR” file entry 819 which stores information regarding the root directory “ROOT_DIR”. Virtual addresses for the file entries stored in the file structure/file area 833 are stored in the VAT structure 834.
As described above, in the UDF file system, when a new file and a directory are added to an additionally recordable disc, the information of the added file and directory and a VAT structure for storing a location information for obtaining the information can be updated and recorded. Furthermore, since the VAT structure is arranged at the end of a recorded area (i.e., immediately prior to an unrecorded area), a recording/reproducing apparatus can obtain the latest VAT structure (the VAT structure 834 in FIG. 8) to obtain a directory and file information.
FIGS. 9A to 9C show the respective data structures of the VAT 804, a VAT 812 and a VAT 820 shown in FIG. 8.
FIG. 9A shows a data layout of the VAT 804 before any directory or file is recorded. The VAT 804 contains only the logic address of a file entry for the “ROOT_DIR” as file entries for directories and files.
FIG. 9B is a data layout of the VAT 812 after the directory “DIR_1” is recorded. The VAT 812 respectively contains a file entry logic address for the “DIR_1”, a file entry logic address for the “FILE_A” and a file entry logic address for the “FILE_B” in respective VAT entries 2 to 4. Thus, obtaining the VAT 812 makes it possible to obtain the recording locations (logic addresses) of file entry information of files and directories stored in the file structure/file area 831.
FIG. 9C shows a data layout of the VAT 820 after the directory “DIR_2” is recorded. The VAT 820 respectively contains a file entry logic address for the “DIR_2”, a file entry logic address for the “FILE_C” and a file entry logic address for the “FILE_D” are contained in respective VAT entries 5 to 7 in addition to the data structure of the VAT 812.
As described above, in the DVD-R which is a conventional additionally recordable disc, an additional file recording is achieved by recording the VAT structure, which is an address conversion table for obtaining file and directory information for the end of a recorded area every time an additional recording process is performed.
However, as described in the example of the DVD-R disc, in order to manage a disc having multiple additional recording points, it is necessary to manage a special data structure called the RZones, thus requiring extremely complicated data management. Therefore, the recording apparatus needs to mount functions, such as an RZone reservation process, a closing process and an RZone-state management process. For example, when a DVD-R recording apparatus is used with a personal computer, the user must execute a special dedicated application corresponding to the RZone management in order to perform recording.
Another problem is that the startup time is increased since the recording apparatus searches for additionally recordable areas in all RZone as described with reference to the process flow of the recording apparatus when a disc is loaded shown in FIG. 3.
A further problem is that all the data structures recorded on the disc can be managed at the file system level as described with reference to FIGS. 8 and 9A to 9C, but is redundantly managed together with an area management using RZones. Therefore, the entire system tends to be complicated.
The present invention solves the above-described problems. The objective thereof is to provide an information recording medium for managing only one recorded-area end location on a disc, a recording apparatus for recording information to the information recording medium and an information reproducing apparatus for reproducing the information on the information recording medium.